Biology: Evolutionary Principles

Evolution

Definition

• Evolution: the scientifically supported theory that all species of life have developed from a common ancestor through the process of natural selection, genetic drift, mutation, and gene flow.

Key Principles

• Descent with modification: all living organisms share a common ancestor and have evolved over time through the accumulation of genetic changes.
• Variation and mutation: genetic variation exists within populations, and mutations can occur, providing the raw material for evolution.
• Heritability: the transmission of traits from one generation to the next through the passing of genetic information.
• Adaptation: the process by which organisms become better suited to their environment, increasing their chances of survival and reproduction.

Mechanisms of Evolution

• Natural selection: the process by which individuals with favorable traits are more likely to survive and reproduce, passing those traits to their offspring.
  • Artificial selection: human-induced selection, such as in breeding programs.
• Genetic drift: the random change in the frequency of a gene or genetic trait in a population over time.
• Gene flow: the movement of genes from one population to another, leading to genetic changes.
• Mutation: changes in the DNA sequence of an individual, which can result in new traits or changes to existing ones.

Evidence for Evolution

• Fossil record: the chronological record of fossils, showing the gradual changes in life forms over time.
• Comparative anatomy: the study of the structure and development of body parts in different species, revealing similarities and homologies.
• Molecular biology: the study of DNA and protein sequences, demonstrating the relatedness of different species.
• Biogeography: the study of the geographic distribution of species, which can be explained by their evolutionary history.

Types of Evolution

• Microevolution: small-scale changes within a population over a relatively short period of time.
• Macroevolution: large-scale changes over a longer period of time, resulting in the formation of new species.
• Co-evolution: the evolution of two or more species that interact closely, such as predator and prey.

Evolution

Definition

• Evolution is the scientifically supported theory that all species of life have developed from a common ancestor through natural processes.

Key Principles

• All living organisms share a common ancestor and have evolved over time through genetic changes.
• Genetic variation exists within populations, and mutations can occur, providing the raw material for evolution.
• Traits are transmitted from one generation to the next through the passing of genetic information.
• Organisms adapt to their environment, increasing their chances of survival and reproduction.

Mechanisms of Evolution

• Natural selection: individuals with favorable traits are more likely to survive and reproduce, passing those traits to their offspring.
• Artificial selection: human-induced selection, such as in breeding programs.
• Genetic drift: random change in gene frequency in a population over time.
• Gene flow: movement of genes from one population to another, leading to genetic changes.
• Mutation: changes in DNA sequence, resulting in new traits or changes to existing ones.

Evidence for Evolution

• Fossil record: chronological record of fossils, showing gradual changes in life forms over time.
• Comparative anatomy: study of body part structure and development in different species, revealing similarities and homologies.
• Molecular biology: study of DNA and protein sequences, demonstrating the relatedness of different species.
• Biogeography: study of geographic distribution of species, explained by their evolutionary history.

Types of Evolution

• Microevolution: small-scale changes within a population over a relatively short period of time.
• Macroevolution: large-scale changes over a longer period of time, resulting in the formation of new species.
• Co-evolution: evolution of two or more species that interact closely, such as predator and prey.